In recent years, various types of biosensors which utilize a specific catalytic action by an enzyme have been developed, and attempts have been made to apply these biosensors to a clinical field. A biosensor which can speedily and accurately perform measurement is desired.
When a glucose sensor is cited as an example, conventionally, a patient measures plasma by centrifuging blood in order to measure and manage a blood sugar level, which results in considerably complicated procedures. Therefore, a sensor which enables measurement of whole blood is desired in these days of rapid increase in the number of diabetic patients.
There is a simplified form, in which a stick-type support body is provided with a carrier including an enzyme that reacts only to sugar (glucose) and a color matter which is changed during an enzyme reaction or by a product of the enzyme reaction, similar to examination paper used during a urine examination. This is a method in which blood is dropped on the carrier to visually or optically measure the change of the color matter after a certain period of time. However, according to this method, accuracy becomes low due to large interference by a coloring substance in the blood.
On the other hand, a measuring system which is disposable with an electrode system at every measurement has also been proposed. While the measuring operation is considerably simplified, such a measuring device system becomes very expensive in view of an electrode material such as platinum and the like, or the construction. While a sputtering method or a deposition method can be employed as a manufacturing method of platinum electrodes, the manufacturing cost is very high.
A biosensor disclosed in Japanese Published Patent Application No. Sho. 61-294351 is proposed as a method which makes the measuring device disposable with an electrode system. According to these measurements, prescribed voltage is applied to an electrode system of the sensor to measure a value of an electric current flowing between electrodes, and concentration of a substrate in a sample liquid is calculated based on the signal. Conventionally, as illustrated in FIG. 7, aluminum package material 40 for packing a sensor 29 is opened to a prescribed position, and the sensor is inserted to a connector part of a measuring device 54, which holds the sensor pinched by the aluminum package 40. Then, after conforming by a display means 30 that the power is automatically turned on, blood is applied to the edge of the sensor 29, thereby performing a measurement.
According to a measuring system having the conventional construction, a connector part of the measuring device is small and its position is hard to be found, so that it is difficult to determine a position to insert the sensor to the connector part of the measuring device or to apply blood of a fingertip or the like to a prescribed position of the sensor. Particularly, the handling is considerably difficult for a blind person or a person having weak eyesight.
The present invention is made to solve the above-mentioned problems. In particular, its object is to provide a measuring system in which an insert position of a sensor and an applying position of blood or the like in a measuring device are easy to be found by attaching a guide for a fingertip. Thus, a specified component in a biological sample such as blood can be easily, speedily, and accurately measured.